Hitherto, as an input device of an information processing apparatus, a touch panel is known. The touch panel is equipped to the screen of an image display device and provides a predetermined instruction to an information processing apparatus by the position in the screen pressed. The outermost surface of the user's side of a large number of image display devices including an image display device mounted with a touch panel is provided with a hard coated film for scratch prevention.
In addition, opportunities to use an image display device outdoors have been increased along with the popularization of portable information devices such as a mobile phone or a notebook-sized personal computer, and a PDA (personal digital assistant). A hard coated film of the image display device for outdoor applications is required to have an excellent resistance to ultraviolet rays. It is needed the hard coated film does not turn yellow and the hard coating layer does not peel from the base film even exposed to ultraviolet rays for a long period of time.
A hard coated film has been formed on the surface not only of these touch panels or image display devices for outdoor applications, but also of a plastic molded product or a paint product such as a protective film or light shielding film for window glass of building or vehicle. These hard coated films have been formed in order to protect these surfaces and to provide excellent scratch resistance and stain resistance to these surfaces. However, these hard coated films themselves are degraded as exposed to ultraviolet rays for a long period of time, and thus peeling, cracking, or discoloration of the hard coated film gradually proceeds. In order to prevent such degradation, various means have been attempted. One of them is adding an ultraviolet absorber to the hard coated film so that durability to ultraviolet rays thereof can be improved.
It is preferable to use an organic resin composition as a material to form a hard coating layer since the hard coating layer can be easily formed by coating. Heating is required to cure the hard coating layer when a thermosetting resin is used as the resin. However, heating is undesirable since deformation of film or the like occurs by heating in a case in which the base material is a thin film. For this reason, a photocurable resin such as an ultraviolet curable resin to be cured by ultraviolet rays is generally used as a resin constituting the hard coating layer of hard coated film.
However, there is a problem that the hardness of coated film may be insufficient or the adhesion between the base film such as polyethylene terephthalate and the hard coated film may deteriorate by the influence of the ultraviolet absorber added in a case in which an ultraviolet curable resin is used as the resin constituting the hard coating layer.
Hence, Patent Literature 1 suggests a hard coated film, in which a hard coating layer containing an ultraviolet absorber, for example a benzotriazole-based compound, having a radically polymerizable (meth)acrylic functional group is formed on a base film. It is described that a large amount of ultraviolet absorber can be contained without imparting the hardness of the hard coating layer and thus a hard coating layer exhibiting high hardness and excellent ultraviolet absorption capacity can be realized in this case. However, the benzotriazole-based ultraviolet absorber does not exhibits satisfactory absorption wavelength or absorption capacity, and thus the effect thereof is insufficient.
Meanwhile, Patent Literature 2 suggests a triazine-based ultraviolet absorber having a (meth)acryloyl group. However, the use thereof to a photocurable composition is not described in this literature, and thus it is not possible to obtain the knowledge related thereto.